A well known 18 year old graffiti artist that goes by the name "Skullphone" has expanded his repertoire of vandalism to include 10 digital billboards around L.A. Earlier this week, onlookers were treated to Skullphones's calling card in between the normal ads running on the display. Nice work dude, let's hope that the police and the folks at ClearChannel appreciate art. Updated: Apparently, it wasn't a hack, but a two-day paid "art project." [Skullphone and Curbed L.A. via Textually and Supertouch]